That is true to an extent, but some concepts held by Japanese tend to be more widely held than in most other cultural groups I have met. Americans that haven't traveled abroad still tend to think the US is the best place to live. Those of us who have seen outside have different opinions, depending on where you live.

I think other nationalities tend to ask more questions than educated Japanese do, and not assume so much. Can't dismiss it by the number who travel (a lot of japanese have a passport), but when they travel, do they really see?